Machining-Induced Surface Damage

Beryllium Manufacturing Processes

“…36 Government regulations limit the maximum in-plant atmospheric concentration of beryllium to 2 µg/m 3 (probably, this will soon be changed to 0.2 µg/m 3 ) as an average concentration for an 8-hour day. 9,38 Exposures to 25 µg/m 3 for up to 30 min. are allowed, but, concentrations over this amount is unallowable for any period of time.…”

“…Polishing of the machined workpiece must be done in a glovebox or, if using a lathe, under a hood. 38 Hazards and protective measures associated with beryllium operations are discussed in a report (soon to be published by author) dealing with these subjects.…”

“…43 The ASM Handbook states that typical machining damage ranges from 0.025 to 0.10 mm for most machining and may extend to a depth of 0.50 mm depending on the machining method. 38 Brush Wellman states that with good practice the damaged layer should generally not exceed a depth of 51 µm (0.002 in. ); however, under severe machining, depths of 0.254 mm may be obtained.…”